Pediatric chronic pain is a critical national health problem resulting in high levels of healthcare utilization. The physical and psychological consequences associated with chronic pain impact overall health and can predispose the development of adult chronic pain. Examining brain-behavior relations among children with chronic pain is essential as psychosocial processes reciprocally interact with physiologic processes to influence pain outcomes. The proposed research utilizes neuroimaging (fMRI) and psychophysiological techniques to enhance our understanding of these relations. Pain-related fear, an essential construct associated with the maintenance of pain-related disability, is the psychosocial process of focus in the current research proposal. The long-term goal of this K23 award is for the candidate to establish a programmatic line of patient-oriented research to integrate behavioral and neuroimaging techniques. The intent is to understand the neural mechanisms of fear and associated negative affect associated with the maintenance of pain-related disability among youth with chronic pain; ultimately characterizing mechanisms of change and treatment responses to psychological interventions targeting children with chronic pain. Complex Regional Pain Syndrome (CRPS) was chosen as a model condition, as a high proportion of patients with CRPS experience persistent pain-related fear. The primary training objective is to acquire expertise in the use of fMRI for use in future studies. The candidate will accomplish this through: 1) mentorship in a clinical/research environment, 2) hands-on training in fMRI by the candidate's sponsor and co-sponsors complemented by didactics in fMRI and advanced statistics, and 3) execution of the proposed research plan. Study 1 assesses activation of the amygdala and related areas in association with fear of pain in a cohort of pediatric pain patients with CRPS. Study 2 examines acute and long-term changes in activation of the amygdala and related areas in a cohort of CRPS patients with high fear imaged at admission, discharge, and six months after an intensive pain rehabilitation program where previously avoided and feared activities are confronted. These studies will lay the groundwork for future neural investigations examining pediatric chronic pain and the impact of fear and associated negative affect.